feat(qwen3-tts-cpp): migrate to ServeurpersoCom/qwentts.cpp (streaming, speakers, voice design) (#10316)

* feat(qwen3-tts-cpp): repoint upstream to ServeurpersoCom/qwentts.cpp

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(qwen3-tts-cpp): flatten qt_* ABI into qt3_* purego shim

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(qwen3-tts-cpp): build shim against upstream qwen-core static lib

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(qwen3-tts-cpp): add option/language/voice/sampling parsing

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(qwen3-tts-cpp): add 24kHz WAV encode/decode/stream-header helpers

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(qwen3-tts-cpp): purego backend with streaming, speakers, voice design

Map TTSRequest onto qwentts.cpp: instructions->instruct, voice->named
speaker or clone-reference path, params map->ref_text + sampling. Add
TTSStream over the qt chunk callback.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* test(qwen3-tts-cpp): unit specs + build-gated TTS/TTSStream e2e

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* fix(qwen3-tts-cpp): close defensive PCM-free gap on zero-sample result

Register CppPCMFree before the n<=0 guard so a non-null buffer with zero
samples cannot leak (the C contract returns NULL on failure, so this is
defensive). Raised in code review.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(qwen3-tts-cpp): advertise TTSStream capability

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* chore(qwen3-tts-cpp): update backend index metadata for qwentts.cpp

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* feat(gallery): qwentts.cpp models - base/customvoice/voicedesign, Q8_0 & Q4_K_M

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* docs(qwen3-tts-cpp): release note for qwentts.cpp migration

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* test(qwen3-tts-cpp): cover audio_path voice-cloning fallback

Add resolveRequest unit specs (config audio_path used as the clone
reference when Voice is empty; per-request audio Voice overrides it; a
named-speaker Voice does not trigger cloning) plus a real-inference e2e
that clones from audio_path (confirmed ref_spk_emb=yes in the pipeline).

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

* chore(qwen3-tts-cpp): drop the release-note doc

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-8 [Claude Code]

---------

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

core/config/backend_capabilities.go

@@ -396,10 +396,10 @@ var BackendCapabilities = map[string]BackendCapability{
 		Description:      "Qwen TTS",
 	},
 	"qwen3-tts-cpp": {
-		GRPCMethods:      []GRPCMethod{MethodTTS},
+		GRPCMethods:      []GRPCMethod{MethodTTS, MethodTTSStream},
 		PossibleUsecases: []string{UsecaseTTS},
 		DefaultUsecases:  []string{UsecaseTTS},
-		Description:      "Qwen3 TTS C++ — text-to-speech, C++ backend",
+		Description:      "Qwen3 TTS C++ - text-to-speech with streaming, named speakers, voice design and cloning (qwentts.cpp / GGML)",
 	},
 	"faster-qwen3-tts": {
 		GRPCMethods:      []GRPCMethod{MethodTTS},